1. Field of the Invention
The present invention relates to a door lock and, more particularly, to an electromagnetic door lock and, most particularly, to an electromagnetic door lock for a sliding double door.
2. Background Information
Existing sliding double automatic doors can be added to an access control system, but with limited functions. The sliding double automatic doors are opened and closed remotely by using a programmed timed schedule in the software for such a system. Usually, it is easy to control the opening and closing of a sliding double door. However, closing the sliding double door does not lock the doors. Although the sliding double doors are closed, they can be forced open. Magnetic locks can be installed on a single automatic door, but installation is extremely difficult because the electronics in the door can be damaged during installation. Therefore, careful drilling of the door is required to install the magnetic lock.
All electromagnetic locks are designed for mounting to a stable, non-moveable, door frame. The electromagnetic lock includes an electromagnet portion secured to the door frame and an armature plate or strike plate portion secured to the door. The electromagnet portion has a power cord to selectively power the electromagnet and does not move. The strike plate or armature plate is secured to the door and moves with operation of the door. The electromagnet portion and strike plate portion are mounted either horizontally or vertically to the door and door frame, respectively. When vertical mounted to a hinged door, the faces of two portions of the electromagnetic lock slide across each other as the portions come into alignment prior to locking. This orientation is termed a “shear lock” and special features are designed into the lock to ensure proper alignment and locking. When horizontally mounted, with the electromagnetic portion extending beyond the door frame, the faces of two portions of the electromagnetic lock approach in register as the portions come into alignment prior to locking. Thus, no special features are required to ensure proper alignment and locking.
Single sliding doors can employ electromagnetic locks in the vertical orientation, with the two faces of the portions approaching in register. Electromagnetic locks are seldom installed on sliding double automatic doors because both doors move away from each other in operation, and the sliding doors have an aluminum access panel above the two doors that is fabricated from very thin metal, which provides little support for an electromagnetic lock system. The access panel encloses the door's operating parts and usually lifts up to access these movable parts. To date, in order to lock this type of sliding double doors, an individual must physically lock the doors with a key. This task is eliminated if magnetic locks (solidly installed) are employed. If the locks are vertically installed, the doors are solidly locked until de-energized. Currently this could be done, but is not, because a long cord is required for connection from the lock to the corner of the door. Because both the doors move and the magnetic lock requires a stationary surface, installation is not practical or possible. Only the strike plate is designed to move. The present invention eliminates this problem and allows both the strike plate and magnetic lock to move, thus providing automatic locking of both doors without a key.
Electromagnetic door locks are well known and a number of innovations concerned with electromagnetic door locks have been granted patents. These patents include U.S. Pat. No. 3,354,581 by Dimmitt et al.; U.S. Pat. No. 4,487,439 by McFadden; U.S. Pat. No. 4,562,665 by Blackston; U.S. Pat. No. 4,826,223 by Geringer et al.; U.S. Pat. No. 4,840,411 by Sowersby; U.S. Pat. No. 4,981,312 by Frolov; U.S. Pat. No. 4,986,581 by Geringer et al.; U.S. Pat. No. 5,000,497 by Geringer et al.; U.S. Pat. No. 5,006,723 by Geringer et al.; U.S. Pat. No. 5,016,929 by Frolov; U.S. Pat. No. 5,033,779 by Geringer et al.; U.S. Pat. No. 5,133,581 by Coleman; U.S. Pat. No. 5,641,187 by Frolov; U.S. Pat. No. 5,692,786 by Berger; U.S. Pat. No. 6,007,119 by Roth et al.; U.S. Pat. No. 6,135,515 by Roth et al.; U.S. Pat. No. 6,260,892 by Chang; U.S. Pat. No. 6,722,715 by Chiang; U.S. Pat. No. 6,758,504 by Mandall; and U.S. Pat. No. 6,880,868 by Brami et al.
Applicant has devised an electromagnetic lock assembly that is readily installed on a sliding double door and provides for remote operation to lock and unlock the sliding double door.